xen-netback: enable user to unload netback module

This patch enables user to unload netback module, which is useful when user
wants to upgrade to a newer netback module without rebooting the host.

Netfront cannot handle netback removal event. As we cannot fix all possible
frontends we add module get / put along with vif get / put to avoid
mis-unloading of netback. To unload netback module, user needs to shutdown all
VMs or migrate them to another host or unplug all vifs before hand.

Signed-off-by: Wei Liu <wei.liu2@citrix.com>
Acked-by: Ian Campbell <ian.campbell@citrix.com>¬
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 5 insertions, 0 deletions

diff --git a/drivers/net/xen-netback/xenbus.c b/drivers/net/xen-netback/xenbus.c
index 410018c4c528..d230c145660c 100644
--- a/drivers/net/xen-netback/xenbus.c
+++ b/drivers/net/xen-netback/xenbus.c
@@ -485,3 +485,8 @@ int xenvif_xenbus_init(void)
 {
         return xenbus_register_backend(&netback_driver);
 }
+
+void xenvif_xenbus_fini(void)
+{
+        return xenbus_unregister_driver(&netback_driver);
+}